Have a 2811 and a 2801. The 2801 runs this: c2801-ipbase-mz.124-1c.bin The 2811 runs: c2800nm-ipbase-mz.123-8.T5.bin What does the nm part of the version mean on the 2811? These are just routers we bought as we had some budget and have used them for lab stuff off and on. THanks.